Figure 1

Viral particles were produced by transient transfection of 293 T cells with (right) or without (left) plasmid expressing flagged SIV-Vpx. Supernatants were harvested after 48 hrs and viral particles were purified onto a double-step sucrose gradient prior to WB analysis with the indicated antibodies. The positions of migration of molecular mass markers (in kilodaltons) are indicated on the right.